A cardiac rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. that occurs as a backup pacemakerAn electronic pulse generator that stimulates depolarization of the atria and/or the ventricles. 1. Six Second ECG Guidebook (2012), T Barill, p. 201 when the sinus node fails to initiate an impulse; the junctionConnects the atria to the ventricle and slows the impulse conduction speed sufficiently to allow for atrial kick; the junction consists of the AV node and the bundle of His; the junction is a supraventricular structure. 1. Six Second ECG... typically fires at 40-60/minute; the P wave is either absent or inverted.
A cardiac rhythm is usually named first by the location of the originating impulse. For example, rhythms that begin in the SA nodeThe SA node, usually the dominant pacemaker, is located in the right atrium at the opening of the superior vena cava. The SA (sinoatrial) node is a clump of hundreds of specialized cardiac cells that have the ability to self-initiate... are called sinus rhythms. Rhythms that originate from the AV junctionConducts the impulse through the fibrous plate that separates the atria and the ventricles; consists of the AV node and the bundle of His; functions also to slow the conduction speed to allow for atrial conduction prior to ventricular conduction... are called junctional rhythms. Ventricular rhythms originate in the ventricle.
The heart rateThe number of QRS complexes per minute; note that HR may not equal perfused pulse rate. See also: - Step 1 Heart Rate - Rate - Rule of 300s (Triplicate Method) - Six Second Count - The Caliper Method 1.... is about 58/minute, an acceptable rateHeart Rate; calculated by counting the number of QRS complexes in six seconds and multiplying by 10; rate is also determined by measuring the number of large squares between two R waves; i.e. –1 large square = heart rate of 300/minute.. The QRSThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also... is narrow making it a supraventricular rhythmIf the QRS is narrow, the rhythm originates from a supraventricular site. Otherwise, if the QRS is wide, chances are, the rhythm is a ventricular rhythm. Remember that the ECG is a two dimensional plotting of voltage (height or amplitude).... The P wavesA wave generated from the depolarization of the atria; the P wave is upright when originating from the SA node. The P wave represents the depolarization of the right and left atria. The P wave begins with the first deviation... are absent. The patternPattern refers to the repeating components of an ECG rhythm in a predicative order. An ECG rhythm that is initiated by one of several intrinsic pacemaker sites of a heart will often generate a regular, even rhythm pattern. This can... is regular. The only plausible explanation: the impulse comes from low in the AV junction. This is a junctional rhythm. Since the heart rate is typical for the junction (40-60/minute), this rhythm is called a junctional rhythm.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 104, 112, 115, 199